Sealed container with inner lid

ABSTRACT

A sealed container with an inner lid 1a includes an openable and closable outer lid 3 to cover an opening 24 of a container body 2; and an inner lid 5a including a frame 53 having a flange 52 on its upper end and a circumferential outer side-surface 55, and an easily elastically deformable partition 51 having a dome shape projecting downward inside the frame 53. The outer lid includes a central area 12 having a dome-shaped concave portion inside a top face portion 10, and a peripheral area 13 surrounding the concave portion. The central area faces the partition and the peripheral area contacts the flange portion in a closed state. The central area has an inner surface formed such that, when the partition deforms to project upward, a surface area of the deformed partition is equal to or smaller than an initial surface area thereof.

TECHNICAL FIELD

The present disclosure relates to a sealed container with an inner lid. More particularly, the present disclosure relates to a sealed container with an inner lid to hermitically seal a container body by mounting an inner lid to an opening of the container body.

BACKGROUND ART

A sealed container with an inner lid according to an embodiment of the present disclosure includes a container body an outer lid that covers an opening of the container body and also serves as an external body of the container, and a detachable inner lid that hermitically seals the opening of the container body. In such a sealed container with inner lid, the inner lid has a dish-like structure with an annular frame having a flange on its upper end and a partition wall inside the frame that serves as a bottom surface. The frame of the inner lid is mounted or snugly fitted in the opening of the container body. In such a state, the outer circumferential surface of the frame in the inner lid contacts under pressure against the inner circumference of the opening of the container body, and the lower surface of the flange extending outward from the frame contacts the upper edge of the opening of the container body.

In this type of the sealed container with the inner lid, the degree of sealing of the container body with the inner lid is high. Thus, when the container body is shallow or when the container body is filled with liquid or gel contents nearly up to the opening, the air compression ratio in the container body above the contents will become high when mounting the inner lid to the opening of the container body. That is, as the frame of the inner lid is inserted in the container body, the pressure inside the container body increases. This internal pressure will press the inner lid upward, so that the inner lid cannot be easily mounted to the container body. Even if the inner lid can be mounted, the inner lid might come off due to shock or vibration since the inner lid is being subjected to internal pressure. The inner lid might of course be reliably mounted if it is mounted carefully, while letting the air inside the container body escape. However, in this case, since the inside of the container becomes negative pressure, the inner lid cannot be easily removed.

Patent Document 1 below describes a compact container including an inner dish and a sealing member made of a soft elastic material and having a thin-walled central deformable portion curved in a spherical shell shape. In this compact container it is structured such that when this sealing body is mounted to an opening of an inner dish body, the central deformable portion deforms upward with an increase in internal pressure of the inner dish body so as to absorb the increased internal pressure. That is, the deformable portion functions as a diaphragm.

CITATION LIST Patent Literature

[PTL 1] Japanese Patent Application Laid-open Publication No. 9-285336

BRIEF SUMMARY Technical Problem

In a sealed container with the inner lid according to the present disclosure, a bottom surface functioning as a diaphragm is provided in a dish-shaped flanged inner lid, as in the compact container described in the Patent Document 1. The diaphragmatic bottom surface absorbs the increase in the internal pressure when the inner lid is mounted to the opening of the container body and makes it easy to mount and dismount of the inner lid to the container body. However, in the compact container described in the aforementioned Patent Document 1, the sealing body of the inner lid is substantially disc-shaped, and its peripheral area outside the central deformable area has complicated concave-convex shapes at the upper and lower surfaces thereof. In addition, the lower surfaces of an outer lid and the upper open edges of the inner dish also have concave-convex shapes to match with the above complicated concave-convex shapes of the inner lid. Furthermore, a groove (circumferential engagement groove) is formed around the peripheral edge of the inner lid. The compact container further includes a main body, an outer lid openable and closable with respect to the main body by a hinge, and an assembly ring which is a separate body apart from the inner dish. This assembly ring engages with the circumferential engagement groove of the sealing body, thereby maintaining the shape of the sealing body, which is made of a soft elastic material. Accordingly, in the compact container described in the Patent Document 1, the opening of the inner dish is sealed with the sealing body using the extremely complex structure, and thus it makes difficult to provide such a product at low cost.

The inner lid of the sealed container has a simple structure as it is provided with a partition wall at the inside of the flanged frame. Therefore, if the partition wall functioning as a diaphragm is provided, it becomes unnecessary to form the periphery of the opening of the container body into a special complicated shape and cost reduction is easy. However, the inner lid having a simple structure brings concerns that, if the container body is closed by the inner lid under atmospheric pressure and is then placed in a reduced pressure environment, such as at high altitudes or within a luggage compartment of an aircraft, the contents therein may leak. Specifically, when the surrounding atmospheric pressure reduces, the internal pressure of the sealed container body relatively increases and the diaphragm will be bent upward. Since the periphery of the diaphragm is integral with the inner circumference of the frame, a force is applied in a direction to reduce the diameter of the frame. As hermetic seal between the inner lid and the container body is maintained by pressing the circumferential outer side-surface of the frame of the inner lid against the circumferential inner side-surface of the container body, if the force in the direction of reducing the diameter of the frame is applied, the frame itself will be bent to reduce its diameter. As a result, the degree of hermeticity between the outer circumferential surface of the frame and the inner surface of the container body is lowered, and the contents may leak from the container because of the relative increase of the internal pressure in the container body.

Accordingly, an object of the present disclosure is to provide a sealed container of high reliability with inner lid capable of preventing leakage of contents in a container body even under reduced pressure, while having a simple structure capable of being manufactured at low cost.

Solution to Problem

An aspect of the present disclosure is a sealed container with an inner lid comprising a bottomed container body having an opening on its upper side, an outer lid to cover the opening in an openable and closable manner, and an inner lid to hermitically seal the container body. The inner lid includes a frame having a flange portion on its upper end and a circumferential outer side-surface and a partition formed at and inside the frame. The partition is easily elastically deformable, the circumferential outer side-surface of the frame being closely in contact with an inner surface of the container body on its opening end side in a state in which the inner lid is mounted to the container body. The partition is formed in a dome shape projecting downward in an initial state in which the inner lid is not mounted to the container body, the partition being deformable to a dome shape projecting upward. The outer lid includes a central area having a dome-shaped concave portion inside a top face, and a peripheral area surrounding the concave portion. The central area faces to the partition and the peripheral area is in contact with an upper surface of the flange portion in a closed state in which the inner lid is mounted to the container body and the outer lid covers the opening of the container body. The central area has an inner surface formed so that, when the partition deforms to project upward, a surface area of the partition in a deformed state is equal to or smaller than a surface area of the partition in the initial state.

Further, such a sealed container with an inner lid is provided in which a difference in height between an upper end of the central area and a vertical position of the periphery of the partition in the closed state is equal to or smaller than a difference in height between a lower end of the partition and the vertical position of the periphery thereof, and a surface area of the central area facing the partition is equal to or smaller than a surface area of an upper surface of the partition in the initial state.

It is preferable that the inner lid has a shape in which the periphery of the partition is connected to an inner circumferential upper end of the flange portion.

A sealed container with an inner lid may include a vent allowing communication between the inside of the central area of the outer lid and outside air. Further, it is more preferable that the vent is a groove formed to extend radially outward in at least one of the peripheral area of the outer lid or the upper surface of the flange portion.

A sealed container with an inner lid described by any one of the above can be structured such that the outer lid includes, inside thereof, a mounting mechanism to engage with the upper side surface of the container body, and the outer lid is to be mounted to the container body using the mounting mechanism, when the outer lid is pushed downward from above to the container body so that the opening is closed with the top face portion.

Advantageous Effects

With a sealed container with an inner lid according to an embodiment of the present disclosure, it is possible to manufacture a sealed container with an inner lid at low cost with a simple structure, and also prevent leakage of contents even under reduced pressure. Other effects will be clarified in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an appearance of a sealed container with an inner lid according to a first embodiment of the present disclosure.

FIG. 2 is an exploded perspective view illustrating a sealed container with the inner lid according to the first embodiment of the present disclosure.

FIG. 3 is a diagram illustrating a structure of the inner lid of the sealed container with the inner lid according to the first embodiment of the present disclosure.

FIGS. 4A and 4B are diagrams illustrating movement of the sealed container with the inner lid according to the first embodiment of the present disclosure.

FIG. 5 is an exploded perspective view illustrating a structure of the outer lid (cap) of the sealed container with the inner lid according to a second embodiment of the present disclosure.

FIG. 6 is a diagram illustrating a modification of the inner lid constituting a sealed container with the inner lid according to the first embodiment of the present disclosure.

FIG. 7 is a diagram illustrating another modification of the inner lid constituting the sealed container with the inner lid according to the first embodiment of the present disclosure.

FIGS. 8A, 8B, and 8C are diagrams illustrating a problem of an inner lid to be solved in the present disclosure.

FIG. 9 is a diagram illustrating a problem of an inner lid to be solved in the present disclosure.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure will hereinafter be described with reference to the accompanying drawings. It should be noted that, in the drawings used for the following description, components that are the same or similar are given the same reference numerals and the descriptions thereof may be omitted. A component given a reference numeral in one drawing may not be given the reference numeral in another drawing when it is unnecessary.

First Embodiment

Structure of Sealed Container with Inner Lid

FIG. 1 is an external view illustrating a sealed container with an inner lid (hereinafter referred to as “sealed container 1 a”) according to a first embodiment of the present disclosure. As illustrated in FIG. 1, the sealed container 1 a has a substantially cylindrical shape, and includes a container body 2 to contain contents therein, and a bottomed cylindrical outer lid (hereinafter referred to as “cap 3”) to be mounted from above to the container body 2. Here, it is assumed that a vertical axis 100 of the cylindrical sealed container 1 a is defined as vertical directions and each of the vertical directions is defined such that the side on which the cap 3 is mounted to the container body 2 is the upper side. The cap 3 is open on its lower side, while including a hollow cylindrical barrel portion 31 having a top face portion 10 serving as a top cover and bonded to the upper end of the barrel portion 31. Further, the cap 3 incorporates therein a mechanism for mounting the cap to the container body 2 (hereinafter referred to as “mounting mechanism”). In addition, rectangular holes 32 communicating between the inside and outside are formed in the barrel portion 31, and push buttons 41, which are a part of the aforementioned mounting mechanism, protrude outward through the holes, respectively.

FIG. 2 is a perspective view illustrating the sealed container 1 a disassembled into its constituent members. The container body 2 has a two-tier cylindrical external form in which a hollow cylindrical neck portion 22 of reduced diameter is continuous with the upper side of a bottomed cylindrical storage portion 21 of enlarged diameter that stores the contents, and the upper end of the neck portion 22 forms an opening 24. Further, an inner surface 23 of the container body 2 has a bottomed cylindrical shape with the same diameter as opening 24. The storage portion 21 has a double cylindrical shape, in which a bottomed cylindrical portion of reduced diameter and continuous downward from the neck portion 22 is formed inside the outer cylindrical portion of enlarged diameter.

The neck portion 22 is provided with a projection 26 to be engaged with the mounting mechanism 4 in the cap 3 along the outer circumferential periphery thereof. This projection (hereinafter referred to as “circumferential projection 26”) has a flat lower end surface and a slanted upper surface. The cap 3 includes the barrel portion 31 and the disc-shaped top face portion 10 that are separate members, and the top face portion 10 is bonded to the upper side of the barrel portion 31. It should be noted that, in this example, a hollow cylindrical peripheral wall 14 is formed to extend from the bottom of the top face portion 10, concentrically with the outer periphery of the top face portion 10. A plurality of slits 18 extending in the vertical direction is formed through the peripheral wall 14 at intervals in the circumferential direction such that tongues 17 each are formed between the slits adjacent to each other in the peripheral wall 14, and the tongues 17 are bendable radially outward with the upper end of the peripheral wall 14 serving as a support. The function of the peripheral wall 14 is described later.

The mounting mechanism 4 incorporated in the barrel portion 31 of the cap 3 has a structure in which the aforementioned push buttons 41 are integrally formed to project from two positions on the outer periphery of an elastic oval annular frame (hereinafter referred to as “mounting frame 42”). It should be noted that, in the barrel portion 31 of the cap 3, support tabs 33 to support the mounting frame 42 from below are formed in the inner surface thereof to protrude inward in addition to the holes 32 guiding the aforementioned push buttons 41 therethrough. When the cap 3 having such a structure as described above is assembled, the mounting frame 42 is inserted into the barrel portion 31 from above, and the push buttons 41 are guided outward through the holes 32 of the barrel portion 31 while causing the lower end of the mounting frame 42 to contact the support tabs 33 in the barrel portion 31, and the top face portion 10 is bonded to the barrel portion 31 on the upper end side, thereby closing the opening of the barrel portion 31 on the upper end side.

The push buttons 41 are formed to face each other along the long axis of the oval annular mounting frame 42. When the two push buttons 41 are pushed in together, the oval annular mounting frame 42 elastically deforms such that the short axis thereof increases in a direction of increasing its diameter as the long axis thereof is reduced in a direction of reducing its diameter. Further, protrusions (hereinafter referred to as “engagement protrusions 43”) formed to protrude in a tongue shape are formed in an inner surface on the short axis side of the mounting frame 42. These engagement protrusions 43 are each formed to have a flat upper surface and a slanted lower surface. Then, when the cap 3 in an assembled state is inserted into the neck portion 22 from above the container body 2, the slanted lower surfaces of the engagement protrusions 43 are each brought in contact with the slanted upper surface of the circumferential projection 26 of the neck portion 22, so that the circumferential projection 26 biases the engagement protrusions 43 outward. This elastically deforms the oval annular mounting frame 42 in the mounting mechanism 4 to increase the diameter along the short axis, thereby causing the engagement protrusions 43 to slide over the circumferential projection 26. Then, when the mounting frame 42 returns to its initial oval annular shape, the engagement protrusions 43 are engaged with the circumferential projection 26 in such a state that the flat upper surface of the engagement protrusions 43 and the flat lower surface of the circumferential projection 26 contact each other with face of face, so that the cap 3 is mounted to the neck portion 22. On the other hand, when the push buttons 41 are pushed in a state in which the cap 3 has been mounted thereto, the mounting frame 42 of the mounting mechanism 4 elastically deforms so as to increase the distance of the short axis, to displace the engagement protrusions 43 outward. As a result, the engagement between the engagement protrusions 43 and the circumferential projection 26 is released, so that the cap 3 can be removed upward. It should be noted that, in the aforementioned structure of the engagement between the cap and the container body 2, it is impossible to hermetically seal the opening 24 of the container body 2. Thus, in the sealed container 1 a according to the first embodiment, the container body 2 is hermetically sealed by mounting an inner lid 5 a to the opening 24.

Structure of Inner Lid

FIG. 3 illustrates a structure of the inner lid 5 a. FIG. 3 is a cross-sectional view taken along line a-a in FIG. 2, illustrating the inner lid 5 a when viewed in the direction of arrows a, and is a longitudinal sectional view when the inner lid 5 a is cut along a plane including the vertical direction. The inner lid 5 a is single molded product made of polypropylene. As illustrated in FIG. 3, the inner lid 5 a has a structure in which a sheet-shaped partition 51 serving as a bottom surface is formed inside an annular frame having a flange 52 formed along its upper edge. Specifically, the inner lid 5 a includes a shallow cylindrical frame (hereinafter referred to as “circumferential portion 53”), in which the flange 52 is formed along the upper edge of the circumferential portion 53 and the sheet-shaped partition 51 is formed inside the circumferential portion 53. Further, the partition 51 has its periphery 54 forming a single integral unit with the upper inner edge of the circumferential portion 53 of the flange 52. In this example, the partition 51 has a dome shape projecting downward and is formed to be a thin wall so as to be elastically deformable, while the periphery 54 of the partition 51 has reduced thickness as compared with other regions of the partition 51. The partition 51 is to be deformable in the vertical directions with the thin-walled periphery 54 serving as a support. It should be noted that the material of the inner lid 5 a may be any material as long as it is elastically deformable, such as polyethylene, silicone, rubber, or some other a suitable material.

The sealed container 1 a according to the first embodiment illustrated in FIGS. 1 and 2 has features in the structure of the aforementioned inner lid 5 a and the shape of the inner surface 11 of the top face portion 10 constituting the cap 3. That is, the inner lid 5 a is removably mounted to the container body 2 without difficulty, and the contents of the sealed container 1 a cannot easily leak out even when the sealed container 1 a is under reduced pressure. Hereinafter, the structure in which the cap 3 and the inner lid 5 a are mounted to the container body 2, and the movement of the inner lid 5 a in the sealed container 1 a shall be described.

Mounting Structure of Cap and Inner Lid

FIGS. 4A and 4B illustrate the structures in which the cap 3 and the inner lid 5 a are mounted to the container body 2 and how the inner lid moves. FIGS. 4A and 4B are sectional views where the upper side of the sealed container 1 a is shown as enlarged, wherein FIG. 4A illustrates a state in which the inner lid 5 a is mounted under atmospheric pressure, and FIG. 4B illustrates a state in which the partition 51 is deformed when the internal pressure of the container body 2 has become very high relative to the ambient pressure, for example, when the sealed container is placed in a reduced-pressure environment. First, the structure in which the cap 3 and the inner lid 5 a are mounted to the container body 2 is described with reference to FIG. 4A. When the inner lid 5 a is mounted to the opening 24 of the container body 2, it is formed such that an outer side-surface 55 of the circumferential portion 53 of the annular frame is pressed against the inner surface 23 of the neck portion 22 in the container body 2, so that the interior of the container body is hermetically sealed. As to the inner surface 11 of the top face portion 10, a central portion 12 (hereinafter referred to as “central area 12”) facing the partition 51 has a concave dome shape which is formed of a partial spherical shape, while a peripheral area 13 (hereinafter referred to as “peripheral area 13”) surrounding the central area 12 is shaped to contact to the upper surface of the flange 52 of the inner lid 5 a. Further, the tongues 17 formed in some positions of the peripheral wall 14 each has protrusion 19 formed on the inner surface of the upper end side thereof, and the flange 52 of the inner lid 5 a is supported by these protrusions 19. This brings about a state in which the inner lid 5 a is mounted to the top face portion 10 of the cap as the inner lid 5 a is held inside the peripheral wall 14 of the top face portion 10. In this structure, since the external diameter of the flange 52 is smaller than the internal diameter of the peripheral wall 14, the inner lid 5 a is held inside the peripheral wall 14 with a clearance. As a result, even if the outer lid 10 and the inner lid 5 a are not precisely aligned, the outer peripheral edge of the flange 52 cannot be pressed against the inner surface of the peripheral wall 14, so that the planar shape of the flange 52 and the circumferential portion 53 continuous therewith does not be deformed. That is, the degree of hermeticity of the container body 2 by means of the inner lid 5 a is not degraded. It should be noted that the lower ends of the tongues 17 of the peripheral wall 14 have protrusions 15 projecting inward and these protrusions 15 engage with a ridged portion around the neck portion 22 of the container body 2. This causes the upper surface of the flange portion 52 of the inner lid 5 a to be pressed against the peripheral area 13 of the top face portion 10.

Movement of the Inner Lid

Next, the movement of the inner lid 5 a is described. As illustrated in FIG. 4A, in a state in which the cap 3 is mounted to the container body 2, the flange 52 of the inner lid 5 a is sandwiched between an upper edge 27 of the periphery of the opening 24 of the container body 2 and a lower surface 16 of the peripheral area 13 of the top face portion 10 of the cap 3. The outer side-surface 55 of the circumferential portion 53 of the inner lid 5 a is pressed against the inner surface 23 of the container body 2. As a result, the opening 24 of the container body 2 is hermitically sealed. It should be noted that, at this time of sealing the opening 24 of the container body 2, as the air between an upper surface 7 of contents 6 and a lower surface 56 of the partition 51 is compressed to increase the internal pressure of the container body 2, the elastic partition 51 slightly deforms upward with the periphery 54 thereof serving as its support. Specifically, the partition 51, whose initial shape is a dome shape having a deep bottom as indicated by chain lines in FIGS. 4A and 4B, elastically deforms such that the lower surface 56 of the partition 51 is pushed upward due to the increase of the internal pressure in the container body 2. In this example, it elastically deforms to have a dome shape with a shallow bottom. That is, the amount of increase in the internal pressure is absorbed by expansion of the volume of a closed space 8 formed between the upper surface 7 of the contents 6 in the container body 2 and the lower surface 56 of the partition 51.

However, when the container body with the inner lid is placed under reduced pressure, for example, in the luggage compartment of an aircraft, the internal pressure of the container body 2 becomes much higher than the ambient pressure. Therefore, the partition 51 greatly deforms into a dome shape projecting upward beyond the upper end level of the circumferential portion 53, such that an upper surface 57 of the partition 51 comes to contact the inner surface 11 of the top face portion 10 of the cap la, as illustrated in FIG. 4B. Here, when the difference in height (hereinafter referred to as “initial depth D”) between the vertical position at the periphery 54 of the partition 51 and the lower end point of the partition 51 is smaller than height (hereinafter referred to as “top-face-portion height H”) between vertical position of the periphery 54 of the partition 51 and the highest point of the dome-shaped central area 12 in the top face portion 10, a problem may occur when the difference between the external pressure and the internal pressure of the container body 2 is very high. That is, the partition 51 may expand such that the difference in height (hereinafter referred to as “expanded height h”) between the top of the periphery 54 of the partition 51 and the highest point in the upper surface 57 of the expanded partition 51 exceeds the height corresponding to the length of the initial depth D. Then, when the partition 51 expands such that the deformation height h exceeds a length equal to the initial depth D, the surface area of the partition 51 becomes larger than the initial surface area thereof. However, since the periphery 54 of the partition 51 is connected to the circumferential portion 53, a force in a direction of reducing the diameter is exerted to the flat cylindrical circumferential portion 53. This will degrade the seal between the outer side-surface 55 of the circumferential portion 53 and the inner surface 23 of the container body 2, and the contents 6 may leak out due to the difference between the external pressure and the internal pressure of the container body 2.

Thus, in the sealed container 1 a according to the first embodiment, the height H of the inner surface of the aforementioned top face portion is set to be equal to or smaller than the initial depth D (D≥H), so that the deformation height h is always equal to or smaller than the initial depth D. Accordingly, as illustrated in FIG. 4B, even if the partition 51 having the initial dome shape projecting downward expand or deforms into a dome shape projecting upward such that the upper surface 57 of the partition 51 comes in contact with the inner surface 11 of the top face portion 10 along the inner surface shape of the central area 12, a stress in the direction of reducing the diameter of the partition is not applied to the circumferential portion 53. That is, if the surface area of the upper surface 57 or the lower surface 56 of the partition 51 after deformation is smaller than the initial surface area, a force is applied to the circumferential portion 53 only in the direction of increasing its diameter. As a result, in accordance with such deformation of the partition 51, the outer side-surface 55 of the circumferential portion 53 is pressed more tightly against the inner surface 23 of the container body 2. Thus, in the sealed container 1 a according to the first embodiment, even though the structure of the inner lid 5 a and the structure of mounting the inner lid 5 a to the container body 2 are simple, the contents 6 in the container body 2 can be reliably prevented from leaking out even under conditions of greatly reduced ambient pressure.

Second Embodiment

As illustrated in FIGS. 4A and 4B, in the sealed container 1 a according to the first embodiment, when the cap 3 is in the closed state in which the cap 3 is mounted to the container body 2, the peripheral area 13 of the top face portion 10 in the cap 3 contacts the upper surface of the flange 52 of the inner lid 5 a, resulting to a state that the dome-shaped central area 12 is sealed. The cap 3 according to the first embodiment in the closed state has a constant relative position in the vertical direction with respect to the container body 2, such that the contact state between the lower surface 16 of the peripheral area 13 and the flange 52 is maintained constant. Then, when the partition 51 rapidly deforms upward and the air in the central area 12 is compressed, the air in the central area 12 escapes outward from the contact region between the flange 52 and the peripheral area 13, and thus the deformation of the partition 51 is substantially prevented. Even in the case in which the atmospheric pressure rapidly increase from a state in which the partition 51 is deformed upward, the air (outside air) outside the sealed container 1 a can flow into the central area 12 from the contact region between the flange 52 and the peripheral area 13, so that the deformation of the partition wall downward is rarely prevented. In other words, such a structure is formed that the space between the central area 12 and the partition 51 can temporarily communicate with the outside air of the container body 2 through the upper space of the flange 52.

However, if the peripheral area 13 and the flange 52 are pressed tightly against each other, for example, in such a case that the cap 3 is pressed downward, it may become difficult for the air in the central area 12 to escape outward. The same applies to the case in which the cap is a screw cap. In the screw cap, the contact pressure changes depending on how deeply the screw cap is tightened. When the cap is tightened the contact tightens also, so that the communication path between the central area 12 and the outside air is blocked. Then, when the communication path between the central area 12 and the outside air is blocked, it becomes difficult for the partition 51 to deform. For example, after the deformation of the partition 51, when the sealed container 1 a is placed under reduced pressure and the cap 3 is pressed downward strongly, the space formed between the central area 12 and the partition 51 will still be kept to the negative pressure. Therefore, even if the sealed container 1 a is returned to the atmospheric pressure environment, the outside air will not be introduced into the central area, so that the partition 51 cannot be returned to its downwardly projecting dome shape. Thus, a sealed container is provided in a second embodiment of the present disclosure in which the partition can smoothly deform in accordance with pressure variation in the container body, even in the case in which the peripheral area and the flange are pressed tightly against each other or in the case that the screw cap is tightly mounted to the container body.

FIG. 5 illustrates a structure of a cap 103 of a sealed container according to a second embodiment. FIG. 5 is an exploded perspective view illustrating the cap 103 when viewed from below. It should be noted that the sealed container according to the second embodiment is similar to the sealed container according to the first embodiment except for a part of the structure of a top face portion 110. Hereinafter, the structure and movement of the top face portion 110 according to the second embodiment will be described.

As illustrated in FIG. 5, the cap 103 includes the top face portion 110, the barrel portion 31, and the mounting mechanism 4, as in the first embodiment. However, the cap 103 has vents 111 that communicate between the dome-shaped central area 12 and the outside air. In this example, grooves 111 are formed, as such vents, which extend radially outward from the outer peripheral side of the central area 12 to the outside of the peripheral wall 14 while traversing the peripheral area 13. In the cap 103, the outside of the peripheral wall 14 communicates with the inner surface of the barrel portion 31, which in turn communicates with the outside through the lower end opening of the barrel portion 31 and the holes 32 guiding the push buttons 41 of the mounting mechanism 4 therethrough. As such, in the sealed container according to the second embodiment, air can enter the central area 12 and exit therefrom through the vents 111, so that the partition 51 can smoothly deform.

Other Embodiments

The container body may have any external form and internal structure as long as the inner surface of the container body is pressed against the outer side-surface of the circumferential portion 53 of the inner lid at a place where the circumferential portion 53 of the inner lid is inserted from the opening of the container body.

The partition of the inner lid and the central area of the top face portion in the cap are not necessarily of a partial spherical shell shape as long as it has a dome shape. For example, as in an inner lid 5 b illustrated in FIG. 6, a cross-sectional shape of the partition 51 may have a wavy shape, such as a shape in which the partition 51 projects upward near the center thereof. Further, as in an inner lid 5 c illustrated in FIG. 7, the periphery 54 of the partition 51 may be connected, below the flange portion, to the inner surface of the circumferential portion 53. In this example, the periphery 54 of the partition 51 is connected to the lower end of the circumferential portion 53. It should be noted that, in such an inner lid 5 c, even if the height H of the top face portion 10 is set to be equal to or smaller than the initial depth D of the partition 51, the contents in the container body may result in leaking out in such a case that the sealed container is subjected to extreme environments, for example, with a sudden sharp increase in pressure inside the container, since the speed of elastic deformation of the partition wall does not keep up with the speed of internal pressure rise so that the seal between the outer side-surface of the circumferential area of the inner lid and the inner surface of the container body will be degraded.

FIGS. 8A, 8B, and 8C illustrate a mechanism of leakage of contents in the container body due to the shape of the inner lid 5 c illustrated in FIG. 7. It should be noted that, in a sealed container 1 b illustrated herein, component members of the cap other than a top face portion 210 are omitted. As compared with a state in which the partition 51 projects downward as illustrated in FIG. 8A, when the pressure inside the container body 2 increases and the partition 51 deforms so as to project upward to come in contact with the inner surface 11 of the top face portion 210 as illustrated in FIG. 8B. At this time, even if D≥H, a force in a direction as indicated in an arrow 102 in the drawings is applied to the periphery 54 of the partition 51 so as to reduce the diameter at the lower end side of the circumferential portion 53 as indicated by a hollow arrow 101 in the drawings. Therefore, when the internal pressure of the container body 2 rises sharply, the speed at which the partition 51 deforms does not keep up with the increase in pressure, so that it becomes impossible to ignore this force in the direction of reducing the diameter. Then, as illustrated in FIG. 8C and an enlarged circle 200 in FIG. 8B, the lower end side of the circumferential portion 53 bends inward, so that the seal between the outer side-surface 55 of the circumferential portion 53 and the inner surface 23 of the container body 2 is degraded. Thus, as in a sealed container 1 c illustrated in FIG. 9, in which a structure of a cap is partially omitted, if the peripheral edge portion of the dome-shaped central area 12 in a top face portion 310 is formed so as to come in contact with the upper surface of the periphery 54 in the partition 51, the force (101 in FIGS. 8A-8C) causing reduction in the diameter of the circumferential portion 53 is not generated, since all the region of the upper surface 57 of the partition 51 comes in contact with the inner surface 11 of the top face portion 310 when the partition 51 deforms to a convex shape of projecting upward. It should be noted that, as in the inner lid 5 c illustrated herein, in the case in which the periphery 54 of the partition 51 is connected to the peripheral surface of the circumferential portion 53 below the flange 52, it is necessary that the peripheral edge portion of the central area 12 in the top face portion 310 is inserted in the circumferential portion 53, and thus the top face portion 310 results in having a wall thickness that is greatly different between the central area 12 and the peripheral area 13 which is to come in contact with the upper surface of the flange 52. As a result, in the case in which the top face portion 310 is produced as an integrally molded product by injection molding, its aesthetic appearance can be impaired unless the molding condition is strictly controlled, since so-called “sink marks”, caused by a thinning of the wall where the thickness changes, may be formed. Thus, it is desirable that the periphery 54 of the partition 51 is connected to the circumferential portion 53 at the upper end of the flange 52.

The inner surface shape of the central area of the cap is not limited to a dome shape of a simple spherical shell, but may be a flat cylindrical dome shape that opens downward. Further, the shape may be a dome shape having an uneven inner surface, such as a shape in which the inner surface of the spherical shell is braced. Even if the partition deforms so as to follow such an uneven shape, the force to reduce the diameter of the circumferential area is not applied, in principal, as long as the surface area of the partition after deformation is equal to or smaller than the surface area of the upper surface or lower surface of the partition in the initial state. It is a matter of course that, unless the partition is made of an extremely soft material, the surface shape of the upper surface cannot follow such an irregular shape even if the partition deforms upward to the maximum degree possible, and thus usually becomes a dome shape. Accordingly, as long as the surface area of the central area facing the partition is equal to or smaller than the initial surface area of the partition, it is possible to prevent reduction in diameter of the circumferential area in the inner lid, which is caused by the action illustrated in FIGS. 8A-8C. If the inner surface of the central area has a shape in which the inner surface of the spherical shell is braced, the surface area of the central area facing the partition is the total of the area of the lower edges of the beams and the area of the inner surface of the spherical shell exposed between the beams adjacent to each other. If this total surface area is equal to or smaller than the initial surface area of the partition, reduction in diameter of the circumferential area can be prevented.

If the inner surface of the central area is formed in such a shape that the rate of the surface area of the partition after deformation against the surface area thereof before deformation is 1 or less, the force to reduce the diameter of the circumferential area of the inner lid is not easily created in principal. However, for example, in the case in which the central area has a flat cylindrical dome shape that opens downward, difference in height is created between the periphery of the partition and the periphery of the central area, and the force in a direction of reducing the diameter of the circumferential area may not be ignored, similarly to the action illustrated in FIGS. 8A-8C. Thus, it is preferable that the partition is deformed so as to be smoothly continuous with the inner surface shape of the central area from the periphery of the partition. That is, it is desirable that the partition and the central area have a dome shape smoothly extending from the center of the plane thereof toward the periphery thereof.

In the second embodiment, a hole communicating with the central area may be formed in the top face portion, as a vent. In this case in which the hole is formed as a vent, the hole may be covered with a hand when the cap is being mounted. Thus, it may be more preferable that a groove formed radially outward from the central area is used as a vent. It should be noted that the vent is not necessarily formed in the outer lid, but may be formed in the inner lid. For example, grooves extending radially outward may be formed on the upper surface of the flange portion, and such grooves can be used as vents. It is a matter of course that such vents can also be formed both in the outer lid and the upper surface of the flange portion.

The structure in which the cap is engaged with the container body is not limited to such an embodiment as described above, but, for example, a screw-cap type may be considered. It is a matter of course that the outer lid is not necessarily a cylindrical cap or to be removable, but may be an outer lid with a hinge, such as a cosmetic compact container. In any case, it is only necessary that the difference in height between the upper end of the central area and the position of the periphery of the partition wall when the cap is closed is equal to or smaller than the difference in height between the position of the periphery of the partition and the lower end of the partition in the initial state, and also the surface area of the central area is equal to or smaller than the surface area of the partition in the initial state.

REFERENCE SIGNS LIST

-   1 a-1 c sealed container with inner lid, 2 container body, -   3 outer lid (cap), 4 mounting mechanism, 5 a-5 c inner lid, -   10, 110, 210, 310 top face portion, -   11 inner surface of top face portion, -   12 central area of top face portion, -   13 peripheral area of top face portion, -   21 storage portion of container body, -   22 neck portion of container body, -   23 inner surface of container body, -   51 partition of inner lid, -   52 flange of inner lid, -   53 circumferential area of inner lid, -   54 periphery of partition, -   55 outer side-surface of circumferential area, -   56 lower surface of partition, -   57 upper surface of partition, -   111 vent (groove) 

1. A sealed container with an inner lid, comprising: a bottomed container body having an opening on its upper side, an outer lid to cover the opening in an openable and closable manner and an inner lid to hermitically seal the container body, the inner lid including a frame having a flange portion on its upper end and a circumferential outer side-surface, and a partition formed at and inside the frame, the partition being easily elastically deformable, the circumferential outer side-surface of the frame being pressed against inner surface of the container body on its opening end side in a state in which the inner lid is mounted to the container body, the partition being formed in a dome shape projecting downward in an initial state in which the inner lid is not mounted to the container body, the partition being deformable to a dome shape projecting upward, the outer lid including a central area having a dome-shaped concave portion inside a top face and a peripheral area surrounding the concave portion, the central area facing the partition and the peripheral area being in contact with an upper surface of the flange portion in a closed state in which the inner lid is mounted to the container body and the outer lid covers the opening of the container body, the central area having an inner surface formed so that, when the partition deforms to project upward, a surface area of the partition in the deformed state is equal to or smaller than a surface area of the partition in the initial state.
 2. A sealed container with an inner lid according to claim 1, wherein a difference in height between an upper end of the central area and a vertical position of the periphery of the partition in the closed state is equal to or smaller than a difference in height between a lower end of the partition and the vertical position of the periphery thereof, and the surface area of the central area facing the partition is equal to or smaller than a surface area of an upper surface of the partition in the initial state.
 3. A sealed container with an inner lid according to claim 1, wherein the inner lid has a shape in which the periphery of the partition is connected to an inner circumferential upper end of the flange portion.
 4. A sealed container with an inner lid according to claim 1, further comprising: a vent allowing communication between the inside of the central area of the outer lid and outside air.
 5. A sealed container with an inner lid according to claim 4, wherein the vent is a groove formed to extend radially outward in at least one of the peripheral area of the outer lid and the upper surface of the flange portion of the inner lid.
 6. A sealed container with an inner lid according to claim 1, wherein the outer lid includes, inside thereof, a mounting mechanism to engage with the upper side surface of the container body, and the outer lid is to be mounted to the container body using the mounting mechanism, when the outer lid is pushed downward from above to the container body so that the opening is closed with the top face portion. 